Method of making tires



UNITED STATES PATENT OFFICE.

MELVON A. MARQUETTE. 0F CHICOPEE FALLS, MASSACHUSETTS. ASSIGNOR TO THEFISK RUBBER COMPANY, OF CHICOPEE FALLS. MASSACHUSETTS. A CORPORATION OFMASSACHUSETTS.

Specification of Letters Patent.

Patented June 13, 1922.

No Drawing. Original application filed April 21, 1920, Serial No.375,471. Divided and this application filed January 5, 1922. Serial No.527,233.

To all rr/mm it may concern:

Be it known that l. MizLvox A. MAI;- oi'rz'rrn. a citizen of the l nitedStates of America. residing at (,hico iee Falls. in the county ofHampden and-State of Massachusetts. have invented certain new and usefulImprovements in a Blethod of Making Tires, of which the following is aspecification.

This application is'a division of an application filed by me April 21,1920, Serial No. 375.471. I

My present invention relates to methods of making tire casings. and hasparticular reference to their building and vulcanization.

it has for its object the formation of a tire casing in an expeditiousmanner while reducing the danger of the formation of buckles or wrinklesin the fabric. It has various other objects which will appear from thedescription and claims.

It is a known fact that when tire casings are subjected to the pressureof the usual two-part yulcanizing molds. including a rigid core and anouter split rigid mold the flowing of the rubber as the mold contractsupon it tends to carry the fabric with it. causing buckles at the lineof intersection of the mold sections and waves following approximatelythe pattern of the non-skid tread. This is particularly true in the caseof tire casings built up out of the so-called cord fabric. whichconsists of a series of" cords forming a warp. either with or without aseries of light weft threads. this fabric has less resistance todistortion than the ordinary square-woven fabric. I have found that bystiffening the outer ply or plies of fabric it is possible to maintainthe fabric in the position in which, it 'as laid while the rubber flowsover it. and to thus dispense with the use of water bags. Thisstiffening may be performed in various ways.

For example. I may partially vulcanize'the outer ply or plies of fabricbefore building them into the casing. or even after they are so built.()r I may place over the fabric plies a partially-vnlcanized sheet ofrubber: and l contemplate either partially vulcanizing the cushion stockand the breaker for this purpose. or using a separate sheet ofpartially-vnlcanized rubber.

()ther ways in which any of the layers mentioned above may be stiffenedis by subjecting them to any air drying process rather than to a truepartial vulcanizz-itionz by solutioning the fabric rather than byfrictioning it: or using for such lavcrs a rubber compound that will bestiff when cold. 01' the stock may be frictioned in the usual manner,than partially vulcanized, and a skim coat of uncured rubber appliedbefore building the fabric into the casing. It will be understood thatsuch stock as built into the casing in a partially vulcanized conditionmay be compounded so that it will have its vulcanization completed inthe same time as that necessary for the unvulcanized stock which isbuilt into the casing to become completely vulcanized. as is well.understood in the art. It is not necessary that the stiffened stockmaintain its resistance after it becomes heated. for the deleteriousinitial pressure of the molds occurs when the rubber is cold: and by thetime that the casing has become lvated. the rubber h s flowed to itsultimate position.

There ore another way to accomplish my principal object is by heatingthe outer rubber of the casing sufficiently to soften it but not enoughto materially a lt'ect the bonding rubber of the carcass. Then whilethis outer rubber is warm and the bonding rubber is cold the moldpressure is applied by closing the molds. The result will be to mold thecovering rubber while warm so that it will flowfreely for the moldingoperations without disturbin; the fabric of the casing which is bondedtogether by the stiff cold rubber durin; the movement of the molds. henthe vulcanixin; heat is then applied to the whole casing. the latter hasbeen set in the molds and is held y the mold pressure. or the fabriclayers may be chilled relative to the tread to produce the same relativeeffect.

The results desired may be accomplished either by stiffening the fabricor by warming the outer layers of rubber in preparation for theapplication of the mold pressure. or the two ways may be used together.

llurinc thus described my intention l claim:

1. The method of making tirc casings cornprising the application ofmolding pressure on the casings while the outer portion is softened byheat and the meme portion of the casing is bonded together by coldrubber, and vulcanizing the tires by heat applied to the whole casingafter the latter has been formed underthe molding pressure.

.2. The method of vulcanizing an assembled tire casing comprisingtemporarily subjecting the tread and carcass of the easing to differenttemperatures whereby the tarcass is at a lower temperature than thetread, and then applying molding pressure to, the casing and subjectingthe casing to vulcanizing heat.

3. In a method of vulcanizing articles composed of rubber and fabric andhaving the fabric substantially localized near one face of the article.warming the portion remote from the fabric without effectively heatingthe fabric-containing portion, and then vulcanizing the article.

4. In a method of vulcanizing between rigid molding surfaces articlescomposed of rubher and fabric and having the fabric substantiallylocalized near one face of the article, warming the portion remote/fromthe fabric without effectively heating the fabric containing portion,and then vulcanizing the article while compressed between rigid moldingsurfaces.

v 5. In a method of vulcanizing tire casings between rigid moldingsurfaces,'warming the tread portion relative to the carcass, and thensubjecting the casing to vulcanizing heat.

6. In a method of vulcanizing tire casings between rigid moldingsurfaces, assembling the carcass and tread portions upon a rigid core,warming the tread relative to the carcass, and then vulcanizing thecasing while confined between the core and rigid outer molding surfaces.

7. In the vulcanization of tire casings, warming the tread relative tothe carcass to cause the tread to conform to a molding pressure withoutdisplacing the carcass, holding the casing under molding pressure whilethe tread is warmer than the carcass, and subsequently vulcanizing thecasing.

MELVON A. MARQUETTE,

